JPH0768304B2 - Method for producing chlorinated polyolefin - Google Patents

Description

TECHNICAL FIELD The present invention relates to chlorinating a polyolefin in an aqueous suspension system, and relates to a method for producing a chlorinated polyolefin having excellent thermal stability.

[Conventional technology]

In order to uniformly disperse the polyolefin powder in water, it is necessary to improve the water wettability of the powder surface. A surfactant is generally added for the purpose of improving the wettability with water.

Conventionally used surfactants include anionic surfactants such as alkylbenzene sulfonates, alkylnaphthalene sulfonates, dialkylsulfosuccinates, alkyl phosphates, alkyl sulfate ester salts,
Naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl sulfate ester, also nonionic surfactants such as polyoxyethylene alkyl allyl ether, polyoxyethylene alkyl ether, oxyethylene oxypropylene block polymer, and other polyvinyl alcohol, There are carboxymethyl cellulose, starch, gelatin and the like.

As a method of adding these surfactants, there are a method of adding immediately before or immediately after adding the polyolefin, a method of continuously or dividingly adding during the reaction, and a method of using an antifoaming agent together.

[Problems to be Solved by the Invention]

However, in the conventional surfactants, there is no one which can achieve both the prevention of foaming and the uniform dispersion of particles by adopting any of the above-mentioned addition methods, and the obtained chlorinated polyolefin is also unsatisfactory in terms of thermal stability. However, it was sometimes restricted for applications such as OA equipment and home appliances that require heat resistance.

The present invention has been made for the purpose of providing a method for producing a chlorinated polyolefin excellent in thermal stability by overcoming the drawbacks of the conventional chlorinated polyolefin.

[Means for Solving the Problems]

As a result of intensive studies, the present inventors have found that the use of a specific substance as a surfactant can achieve the above object, and completed the present invention.

That is, in the present invention, when chlorinating a polyolefin in an aqueous suspension system, a metal salt of alkyldiphenyletherdisulfonic acid represented by the general formula [I] below is added as a surfactant. It is a manufacturing method of polyolefin.

(Here, R ₁ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, R ₂ represents an alkyl group having 6 to 36 carbon atoms, and M represents an alkali metal or an alkaline earth metal.) The details will be described.

The polyolefin used in the present invention is a polymer or copolymer of α-olefin, such as polyethylene,
Polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, propylene-butene copolymer,
Examples thereof include polymers such as ethylene-butadiene copolymer and ethylene-acrylic acid ester copolymer.

The molecular weight of the polyolefin used is generally 10,000 to 1,000,000, preferably 40,000 to 400,000.

The particle size of the polyolefin is usually 50 to 1000 μm.

The surfactant in the present invention is a metal salt of alkyl diphenyl ether disulfonic acid represented by the above formula [I]. Here, the metal M is selected from alkali metals or alkaline earth metals, and is preferably lithium, sodium, potassium and calcium.

The amount of the surfactant added is 0.01 to 5 relative to the polyolefin.
% By weight, preferably 0.5-2% by weight.

If the amount added is less than 0.01% by weight, poor suspension dispersion tends to occur, and if it exceeds 5% by weight, foaming increases and the thermal stability of the resulting chlorinated polyolefin decreases, which is not preferable.

Although any conventional method may be used as the method for adding the surfactant, it is preferable to add the surfactant immediately before adding the polyolefin in view of workability.

Regarding the chlorination method of polyolefin, a conventionally used method, for example, JP-A-47-6728 and JP-A-47-82.
The method disclosed in Japanese Patent Laid-Open No. 22 or Japanese Patent Laid-Open No. 51-138791 can be applied. The chlorine content of the obtained chlorinated polyolefin is generally 15 to 55% by weight.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

The reaction conditions and characteristics of the chlorinated polyolefin were determined by the following methods.

Regarding the state during the reaction, the degree of foaming and the state of suspension dispersion were observed through a viewing window, and (1) the degree of foaming was visually evaluated in the following four stages.

⊚: Almost no bubbles ◯: Little bubbles Δ: Many bubbles ×: Very many bubbles (2) Suspension The dispersed state was visually evaluated in the following four stages.

◎: Very good ○: Good △: Bad ×: Very bad (3) The tensile test complied with JIS K6301.

(4) The thermal stability evaluation method showed the appearance change after leaving the sheet in a gear oven at 180 ° C. for 30 minutes in the following three stages.

◎: No change ○: Slightly discolored △: Slightly discolored Example 1 80 L of water in a 100 L autoclave, 80 g of sodium dodecyldiphenyl ether disulfonate as a surfactant and powdered polyethylene (melt index 0.3,
Density 0.956g / cm ³ , average particle size 200μm) 10kg in sequence, 8
Chlorination was carried out at 0-125 ° C to a chlorine content of 35% by weight.

Observation of the inside of the can during the reaction revealed that there was almost no foaming and the particles were in a good state of suspension and dispersion.

Example 2 Sodium dodecyl diphenyl ether disulfonate
Polyethylene was chlorinated under the same conditions as in Example 1 except that the amount was 40 g.

During the reaction, foaming was less than in Example 1, and the particles were in a good suspension / dispersion state.

Example 3 Sodium dodecyl diphenyl ether disulfonate
160 g, powdered polyethylene (melt index 6.
Chlorination of polyethylene was carried out under the same conditions as in Example 1 except that the density was 0, the density was 0.957 g / cm ³ , and the average particle size was 250 μm).

During the reaction, there was almost no foaming, and the suspended and dispersed state of the particles was also good.

Example 4 80 L of water in a 100 L autoclave, 120 g of sodium dodecyl diphenyl ether disulfonate as a surfactant and a powdery ethylene propylene copolymer (melt index 1.6, propylene content 30%, average particle size 180 μ)
m) 6 kg was sequentially added and chlorination was carried out at 70 to 110 ° C. until the chlorine content was 35% by weight.

During the reaction, there was almost no foaming, and the suspended and dispersed state of the particles was also good.

Comparative Example 1 Chlorination was carried out under the same conditions as in Example 1 except that 200 g of polyoxyethylene nonylphenyl ether was used as the surfactant.

During the reaction, foaming was so much that the suspension-dispersed state could not be confirmed. In addition, particles were floated due to poor dispersion during the reaction.

Comparative Example 2 Chlorination was carried out under the same conditions as in Example 1 except that 160 g of sodium dodecylbenzenesulfonate was used as the surfactant.

In addition to a large amount of foaming during the reaction, the suspended and dispersed state was rather poor, and particles were floated due to poor dispersion during the reaction.

Comparative Example 3 Chlorination was carried out under the same conditions as in Example 1 except that 160 g of sodium dodecylbenzenesulfonate was added as a surfactant in divided portions before and during the reaction.

A lot of foaming occurred during the reaction, and the state of suspension and dispersion was slightly better than that of Comparative Example 2.

Comparative Example 4 Chlorination was carried out under the same conditions as in Example 1 except that 160 g of sodium dodecylbenzenesulfonate as a surfactant and 20 g of a silicone defoaming agent containing emulsion type silica gel as a defoaming agent were used in combination.

Almost no foaming was observed in the early stage of the reaction,
The foaming gradually increased, and the defoaming effect was considerably lost in the latter half of the reaction. In addition, the suspension-dispersed state was poor throughout the reaction, and particles floated during the reaction.

The observation results during the reaction are summarized in Table 1 above.

Further, to 100 parts by weight of each chlorinated polyolefin obtained in Examples 1 to 4 and Comparative Examples 1 to 4, 2 parts by weight of dioctyltin maleate polymer (manufactured by Sankyoki Gosei Co., Ltd.) was added as a stabilizer, and the mixture was heated at 130 ° C. Roll kneading for a minute. Each of the obtained sheets was pressed at 140 ° C and 150 kg / cm ² G for 5 minutes to give a thickness of 1
It was used as a test sheet of mm. The results of the physical property test of this sheet are shown in Table 1.

From the results of the above Examples and Comparative Examples, it is clear that the chlorinated polyolefin according to the present invention is rich in elasticity and excellent in thermal stability.

〔The invention's effect〕

The chlorinated polyolefin obtained by the production method of the present invention has excellent thermal stability, and is useful in fields such as OA equipment and home appliances that particularly require heat resistance.

Further, according to the present invention, since the state of suspension and dispersion of particles during the reaction is good, it is possible to increase the amount of polyolefin charged to about twice that in the conventional method, and the industrial effect thereof is great.

Claims (2)

[Claims] 1. A method of chlorinating a polyolefin in an aqueous suspension system, which comprises adding a metal salt of alkyldiphenyl ether disulfonic acid represented by the general formula [I] below as a surfactant. Method for producing polyolefin. (Here, R ₁ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, R ₂ represents an alkyl group having 6 to 36 carbon atoms, and M represents an alkali metal or alkaline earth metal) 2. The method for producing a chlorinated polyolefin according to claim 1, wherein the amount of the surfactant added is 0.01 to 5% by weight based on the polyolefin.